Diazotype materials and methods for producing diazotype images



United States Patent 3,427,162 DIAZOTYPE MATERIALS AND METHODS FOR PRODUCING DIAZOTYPE IMAGES Bernard I. Halperin, Glen Aubrey, N.Y., assignor to International Business Machines Corporation, Armonk,

N.Y., a corporation of New York No Drawing. Filed Dec. 28, 1965, Ser. No. 517,083 U.S. Cl. 9649 7 Claims Int. Cl. G03e 1/58, 5/34 ABSTRACT OF THE DISCLOSURE A method for producing high opacity diazotype images whereby a material containing a light-sensitive diazonium compound is selectively exposed to light so as to decompose said compound in the portion of said material where the light impinges, and whereby substantially anhydrous ammonia is applied at a pressure of about p.s.i.g. to 985 psig, so as to couple said undecomposed diazonium compound with a coupler compound having the formula wherein, in a specific compound, R is other than hydrogen at a 2,3,5-, 2,3,6- or 2,3,5,6-position and 'R is a radical selected firom the group consisting of hydrogen, aryl, alkyl, alkene and aralkyl radicals and said radical is unsubstituted or substituted by radicals selected from the group consisting of carboXy, hydroxy, carbonyl and amino, thereby producing a high opacity image.

This invention relates to diazotype materials and to methods for producing diazotype images. In particular, the invention is concerned with diazo materials capable of yielding high ultraviolet opacity images upon development by the procedure described in U.S. patent application Ser. No. 369,861, filed May 25, 1964, by Boone, et al. for Diazo Development Process. This patent application is directed to the development of diazo images by the application of high pressure ammonia, especially high pressure anhydrous ammonia.

An object of the present invention is to provide diazotype compositions, papers, films and the like which yield high opacity images upon development by high pressure ammonia.

A further object of the invention is to provide diazo materials which exhibit good stability and shelf life, but which are capable of very rapid development by high pressure ammonia.

In general, the invention comprises diazo materials incorporating trior tetra-substituted phenol couplers. The invention further comprises the production of high opacity images by high pressure ammonia development of diazo materials incorporating trior tetra-substituted phenol couplers. The preferred compounds are selected from the group consisting of 2,3,5-, 2,3,6- and 2,3,5,6-substituted phenols.

While the invention is generally applicable to one or two component systems, it is particularly valuable in two component systems. Such systems generally comprise a substrate provided with a coating containing, as the essential ingredients, a light sensitive, diazonium compound and a coupler, in this instance a 2,3,5-, 2,3,6- or 2,'3,5,6- substituted phenol. The coating may also contain an amount of an acid to stabilize the composition against premature coupling. Other coupling compounds may also be added to give a dye image of the desired color upon development. The film or paper element is selectively exposed to light and is then developed by being contacted with high pressure ammonia. The developing agent is preferably anhydrous ammonia.

The couplers incorporated in the diazo materials of this invention are selected from the group consisting of 2,3,5-, 2,3,6- and 2,3,5,6-substituted phenols having the following general formula:

where, in a specific compound, R is other than hydrogen only at the 2,3,5-, 2,3,6- or 2,3,5,6-positions and R is a radical selected from the group consisting of hydrogen aryl, alkyl, alkene or aralkyl radicals. The radicals themselves may be unsubstituted or substituted by a carboxy, hydroxy, carbonyl or amino group and derivatives of any of these groups.

Specific compounds of the foregoing general formula, illustrative of those useful in this invention, include, for example, those in Table I.

TABLE I 2-(N,N-diethyl aminomethyl)-3,6-dimethyl phenol 2,3-dimethyl-S-tertiarybutyl phenol 2,3,6-trimethylphenol 2,3,5-trimethylphenol 2,3,5,6-tetramethylphenol 3,5-dimethyl (N-2-hydroxyethyl) salicylamide 3,6-di-methylsalicylic acid 3,6-dimethyl (N-Z-hydroxyethyl) salicylamide 3-methyl-6-tertiarybutylsalicylic acid 3-methyl-6-tertiarybutyl (N-Z-hydroxyethyl) salicylamide 2-(N,N-dimethylaminomethyl)-3-methyl-6-tertiarybutylphenol In a preferred embodiment of the invention, an organic solution is prepared containing an appropriate light sensitive diazonium salt and 9. 2,3,5-, 2,3,6- or 2,3,5,6- substituted phenol of the type described. Mixtures of the couplers with others of the group or with conventional couplers may also be employed. A coating of the solution is deposited onto a suitable substrate and is dried. The substrate may comprise a transparent film support of cellulose acetate, a paper web or any other suitable substrate material.

Any of the conventional, well known, light sensitive diazonium compounds may be employed in preparing the diazo materials of the invention.

The resulting diazo material is then selectively exposed to light to decompose the light sensitive diazonium compound in those areas where no image is desired.

The exposed diazo element is then developed by heing subjected to high pressure ammonia, preferably anhydrous ammonia. Application of the ammonia brings about a very rapid coupling of the uudecomposed por tion of the diazonium compound and the coupler compound. The anhydrous ammonia is applied at a pressure significantly in excess of atmospheric pressure. For example, a pressure in the range of from about 35 to 985 p.s.i.g. absolute is satisfactory. With diazo materials of the type described, development is substantially completed in about 1 second or less upon exposure to high pressure ammonia, preferably anhydrous ammonia.

The following detailed examples of preferred embodiments of the invention will assist towards a fuller understanding of the invention.

Example 1 As a specific example of the diazo materials and image forming process of the invention, diazo elements are produced and images formed in the following manner.

A solvent solution is prepared by mixing 30 parts by volume of methyl ethyl ketone with 40 parts by volume of methyl Cellosolve. The following ingredients are then dissolved in the solvent solution in the indicated percentages by weight:

Percent Citric acid 2 Sulfosalicylic acid l p-Dimethylamino benzene fiuoborate 1.5 3,5-dimethyl (N-2-hydroxyethyl)salicylamide 2.0

A thin coating of the resulting solution is deposited onto a transparent cellulose acetate substrate and the coating is allowed to dry. The element is then exposed to light through a negative for from about 3 to 5 seconds and is developed by contact with anhydrous ammonia at a pressure of 80 p.s.i.g. for 1.0 second. This produces a fully developed, high opacity, image.

Example 2 The invention may also be practiced using diazo formulations comprising a resinous carrier or vehicle. Materials of this type are prepared and images are produced from such materials in the following manner:

A solvent solution is prepared by mixing 33 parts by volume of methyl ethyl ketone with 44 parts by volume of methyl Cellosolve. The following ingredients are then dissolved in the solvent solution in the indicated percentages by weight:

Percent Bakelite Ayat 1.12 Rohm & Haas B-82 Acryloid 0.75 Sulfosalicylic acid 1.0 Citric acid 2.0 p-Dimethylamino benzene fluoboraate 1.5 3-methyl-6-tertiarybuty1 salicylic acid 2.0

A thin coating of the resulting solution is deposited onto a transparent cellulose acetate substrate and is dried, exposed and developed as in Example 1. A fully developed, high opacity image is produced.

Example 3 Diazo material is prepared as in Example 2, but 3,6- dimethyl salicylic acid is substitutedas the coupler.

Example 4 made at p.s.i.g. for 1.0 second in all cases. Compara tive data are tabulated in Table I.

TABLE II.METHOD OF DEVELOPMENT Anhydrous Aqueous ammonia, ammonia, 1.0 sec., p.s.i.g. (Ozamatic) Coupler Total Density No. of dwell Denslty (D'7-51) passes time (D 751) (see) It will be noted that in none of the cases of the representative examples cited did aqua ammonia development for 20 seconds produce an optical density equivalent to that produced by anhydrous ammonia at 80 p.s.i.g. for one second. 4

In Table II, D7-51 refers to the density of the image produced as measured by a standard densitometer provided with a 7-51 wavelength filter. As shown by the data in Table II, diazo elements comprising standard diazotype formulations incorporating couplers of the present invention yield images of satisfactory density or opacity upon development for only 1 second with high pressure, anhydrous ammonia. The same elements do not provide images of comparable density after numerous passes through a conventional aqueous ammonia developing unit. The accumulated development time in the aqueous ammonia unit is at least twenty times greater than the time required for development of such materials with high pressure, anhydrous ammonia. This demonstrates the unique suitability of the diazo materials of the invention for high pressure ammonia development and their lack of practical utility in conventional diazotype development processes.

Comparable results are obtained with diazo materials comprising conventional light sensitive diazonium compounds and any of the described 2,3,5-, 2,3,6- or 2,3,5,6- substituted phenol couplers upon development with high pressure ammonia.

Although this invention has been generally described in terms of developing diazo-type images in two component systems, namely those containing both a diazonium compound and a coupler compound in the same element, it should be clearly understood that this invention is intended to have general applicability to one component elements as well. In the latter case, the coupler is contacted with the undercomposed diazonium compound by application of the coupler compound to the element after exposure.

It will be apparent to those skilled in the art that certain modifications may be made in the method and formulations described herein without departing from the spirit or scope of the invention as expressed in the following claims.

What I claim is:

1. A method for producing high opacity diazo-type images comprising selectively exposing to light a layer of material containing a light-sensitive diazonium compound so as to decompose said compound in a portion of said layer where the light impinges and where no azo dye formation is desired, applying substantially anhydrous ammonia at pressure of about 35 p.s.i.g. to 985 p.s.i.g. to said undecomposed diazonium compound with a coupler compound having the formula wherein, in a specific compound, R is other than hydrogen at a 2,3,5-, 2,3,6- or 2,3,5,6-positions and R is a radical selected from the group consisting of hydrogen, aryl, alkyl, alkene and aralkyl radicals and said radicals are unsubstituted or sustituted by a radical selected from the group consisting of carboxy, hydroxy, carbonyl and amino, thereby producing a high opacity image.

2. The method of claim 1 wherein said undecomposed diazonium compound is contacted with said coupled by mixing said coupler compound with said light sensitive diazonium compound in said layer prior to exposure.

3. The method of claim 1 wherein said coupler is contacted with said undecomposed diazonium compound by application to said layer after exposure.

4. The method of claim 1 wherein R is an aryl radical.

5. The method of claim 1 wherein R is an alkyl radical.

6. The method of claim 1 wherein R is an alkene radical.

7. The method of claim 1 wherein R is an aralkyl radical.

References Cited FOREIGN PATENTS 5/ 1961 Great Britain. 9/1963 Great Britain. 11/ 1963 Great Britain. 1/ 1965 Great Britain.

J. TRAVIS BROWN, Primary Examiner.

C. BOWERS, Assistant Examiner.

US. Cl. X.R. 

